• Tight PSR CC/CV Regulation Over Entire Operating Range
• QR-mode Operation for High Efficiency
• PWM/PFM Control for High Average Efficiency
• Programmable Soft Start
• Low Start Up Current: 5μA Max 
• Minimum Frequency Limitation 2kHz
• Reliable Protections for OVP, SCP, OTP,OCP
• Reliable Protections for Safety Requirement
• Maximum switching frequency limitation125kHz
• Integrated 200V/0.33Ω MOSFET
• Compact Package: SO8

SY22857 is a single stage Flyback regulator targeting at Telecom adapters or chargers applications. It integrates a 200V/0.33Ω MOSFET in a compact SO8 package to minimize the size. Both the output current and voltage are sensed on the primary side, eliminating the opto-isolator and the secondary side feedback circuitry, and minimizing the overall system cost.

SY22857 adopts the quasi-resonant operation and the adaptive PWM/PFM control to achieve the highest average efficiency and the best EMI performance.

SY22857 has programmable soft start to reduce the input inrush current while power on.

SY22857 provides reliable protections including VIN over voltage protection, short circuit protection (SCP), over temperature protection (OTP), output over voltage OVP protection (OVP), ZCS/ISEN pin short protection, and ZCS pin upper divider resistor disconnect protection.